The Glaser Safety Slug was designed in 1974 in response to the possibility of having to use a handgun on an airplane by the Sky Marshals. The concerns at that time were over penetration on soft tissue and ricochets on hard surfaces and possible excess penetration. In 2002, we purchased the company, because we knew that Safety Slug would be a perfect compliment to the COR-BON family of products and a great home defense round. Specifications and Features: Caliber: 9mm Luger +P Bullet Wt.: 80gr Glaser Safety Slug Velocity: 1500fps Energy: 399ftlbs Test Barrel Length: 4.0 Inches Rounds: 20 rounds per box.